New technology for photogrammetry... Comments

New technology for photogrammetry... Comments

Posted by JohnHalleck on May 22, 2011 7:53 pm

http://www.smartertechnology.com/c/a/Smarter-Strategies/Cloud-Makes-3D-Models-from-Ariel-Photos/

I have mixed feeling about this.

Theory:
From a number of overlapping photos, common points can be determined, and the viewpoint of each picture (relative to the view points of the other pictures) can be computed straight forwardly, and given the calculations of the view points of each, and identifiying the 3D coordinates is (in the mathematical sense) of points in overlap areas can be assigned 3 D coordinates.
You'd want at LEAST 50% overlap (I.E. every  point on the ground appears in at least two pictures.)

Practice:
The accuracy varies, based on the usual "strength of figure" arguments in a new guise.  What people get is basicly a point cloud, without a clue as to the accuracy of the individual points, without the viewpoint relationships (and coordinates), and with an assumed level.

Social issues:
The ads are already calling the result a "map", and people will get points to a gazillion digits...  most of which won't be significant in any way.
And, I'm told, you can soon have the original pictures drapped over the new 3d surface.
It will, in my opinion, the same issues dealing with some GIS newbies now:  "I was given 20 digits, I must have 20 digits of accuracy."

Bright side:
In the right hands, with some identifiable control points, and some software to rotate/scale/fit the cloud to control points, this could be a cheap fast way of getting a 3d model of what the land and structures look like.

------------------------------------------------- The root word for the English "Amateur" is the Latin "amare" which means "to love". So if I say I'm a survey amateur, that doesn't mean I survey amateurs.

Re: New technology for photogrammetry... Comments

Posted by Mike Falk on May 22, 2011 9:07 pm

John

Check out Blaise Aguera y Arcas demos Photosynth
http://www.ted.com/talks/blaise_aguera_y_arcas_demos_photosynth.html

Re: New technology for photogrammetry... Comments

Posted by Andrew Gaiennie on May 23, 2011 6:52 am

SO what if a surveyor were to apply their professionalism to the collected photos, so they did have a reference and consistancy (RTN+synced cameras maybe)? I would think this is a cheap way for survey firms to start using both the cloud and 3D modeling in their practises. And while I would kill(almost) to use a drone in my work, I'm preaty sure its still not considered best practise untill the FAA decides its ok for commercial services.

Thanks for the info! 

Mr. Falk,

To get a good 3D model from Photosynth, some guy came up with a nice system and posted it on youtube. I was impressed, you should check it out.